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Optimal way of deleting huge numbers of files

Using xargs is better than: find /path/to/dir -type f -exec rm \-f {} \; as the -exec switch uses a separate process for each remove. xargs splits the streamed files into more managable subsets so less processes are required.
This is sample output - yours may be different.
12

find /path/to/dir -type f -print0 | xargs -0 rm

root · 2009-01-26 11:30:47 63
Display PHP files that directly instantiate a given class

This greps all PHP files for a given classname and displays both the file and the usage. Show Sample Output
This is sample output - yours may be different.
```
tao/tests/filter/TestUrl.php:        $this->objFilter = new filter_Url();
tao/classes/local/view/Photos.php:        $objFilter  = new filter_Url();
```
1

find . -name "*.php" -exec grep \-H "new filter_" {} \;

root · 2009-01-26 10:43:09 73
Run the last command as root

Useful when you forget to use sudo for a command. "!!" grabs the last run command.
This is sample output - yours may be different.
1219

sudo !!

root · 2009-01-26 10:26:48 263
Creates a customized search command

Creates a command alias ('cr' in the above example) that searches the contents of files matching a set of file extensions (C & C++ source-code in the above example) recursively within the current directory. Search configured to be in colour, ignore-case, show line numbers and show 4 lines of context. Put in shell initialisation file of your choice. Trivially easy to use, e.g: cr sha1_init Show Sample Output
This is sample output - yours may be different.
```
./openssl/signatures.c-600-xmlSecOpenSSLDsaSha1EvpInit(EVP_MD_CTX *ctx)
./openssl/signatures.c-601-{
./openssl/signatures.c:602:    return SHA1_Init(ctx->md_data);
./openssl/signatures.c-603-}
./openssl/signatures.c-604-
--
./openssl/signatures.c-706-    NULL,
./openssl/signatures.c-707-#else /* XMLSEC_OPENSSL_096 */
./openssl/signatures.c:708:    SHA1_Init,
./openssl/signatures.c-709-    SHA1_Update,
./openssl/signatures.c-710-    SHA1_Final,
```
0

alias cr='find . 2>/dev/null -regex '\''.*\.$c\|cpp\|pc\|h\|hpp\|cc$$'\'' | xargs grep --color=always -ni -C2'

chrisdrew · 2009-01-26 08:54:25 56
Outputs a sorted list of disk usage to a text file

Recursively searches current directory and outputs sorted list of each directory's disk usage to a text file. Show Sample Output
This is sample output - yours may be different.
```
712     .
328     ./test
176     ./lib
144     ./doc
100     ./test/data
96      ./lib/rake
64      ./doc/release_notes
```
6

du | sort -gr > file_sizes

chrisdrew · 2009-01-26 01:12:54 62
Watch how fast the files in a drive are being deleted

This can be useful when a large remove operation is taking place.
This is sample output - yours may be different.
6

watch "df | grep /path/to/drive"

root · 2009-01-25 21:16:41 674
Execute a command at a given time

This is an alternative to cron which allows a one-off task to be scheduled for a certain time.
This is sample output - yours may be different.
266

echo "ls -l" | at midnight

root · 2009-01-25 21:07:42 86
Analyse an Apache access log for the most common IP addresses

This uses awk to grab the IP address from each request and then sorts and summarises the top 10.
This is sample output - yours may be different.
22

tail -10000 access_log | awk '{print $1}' | sort | uniq -c | sort -n | tail

root · 2009-01-25 21:01:52 47
Add SVN keywords property to all PHP and Javascript files
This is sample output - yours may be different.
3

find . $ -name "*.php" -o -name "*.js" $ -exec svn propset svn:keywords Id {} \;

root · 2009-01-24 00:54:35 63
Count files beneath current directory (including subfolders)
This is sample output - yours may be different.
18

find . -type f | wc -l

root · 2009-01-23 17:19:32 74

Display the top ten running processes - sorted by memory usage

ps returns all running processes which are then sorted by the 4th field in numerical order and the top 10 are sent to STDOUT. Show Sample Output

106

ps aux | sort -nk +4 | tail

root · 2009-01-23 17:12:33 295

Checks all MySQL tables

See http://dev.mysql.com/doc/refman/5.0/en/myisamchk.html for further details. You can also repair all tables by running: myisamchk -r *.MYI
This is sample output - yours may be different.
-2

myisamchk /path/to/mysql/files/*.MYI

root · 2009-01-22 10:20:00 133
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Get the total length of time in hours:minutes:seconds (HH:MM:SS) of all video (or audio) in the current dir (and below)

change the *.avi to whatever you want to match, you can remove it altogether if you want to check all files.

Encode/Decode text to/from Base64 on a Mac w/out Mac Ports

I have a mac, and do not want to install mac ports to get the base64 binary. Using openssl will do the trick just fine. Note, to decode base64, specify a '-d' after 'base64' in the command. Note also the files base64.decoded.txt and base64.encoded.txt are text files.

Get a BOFH excuse

Gets a BOFH excuse from the BOFH excuse server (towel.blinkenlights.nl port 666), and passes it through sed and tr to get rid of telnet connection stuff.

List subfolders from largest to smallest with sizes in human readable form

Force an fsck on reboot

Force an fsck on reboot. Useful on a system where / has mounted read-only because of file system issues.

Retrieve a random command from the commandlinefu.com API

Seeing that we get back plain text anyway we don't need lynx. Also the sed-part removes the credit line.

List all packages in Ubuntu/Debian that no package depends on

Decode base64-encoded file in one line of Perl

If you are in an environment where you don't have the base64 executable or MIME tools available, this can be very handy for salvaging email attachments when the headers are mangled but the encoded document itself is intact.

Return threads count of a process

Source: http://superuser.com/questions/49408/how-do-i-monitor-or-view-the-thread-count-of-a-certain-process-on-aix

Losslessly rotate videos from your phone by 90 degrees.

Takes all the .3gp files in the directory, rotates them by 90 degrees, and saves them in the lossless ffv1 encoding. If this rotates in the wrong direction, you may want transponse=1 Re-encoding to ffv1 may result in a significant increase in file size, as it is a lossless format. Other applications may not recognize ffv1 if they don't use ffmpeg code. "huffyuv" might be another option for lossless saving of your transformations. The audio may be re-encoded as well, if the encoding used by your 3gp file doesn't work in a avi container.

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